Reflux esophagitis is a common complication following distal gastrectomy. According to the investigators preliminary data, an Roux-en--Y gastrointestinal reconstruction in pancreaticoduodenectomy is associated with higher rates of reflux esophagitis. In this study, the investigators will investigate the incidence of reflux esophagitis after above procedure by the 24-h pH monitoring of esophagogastric junction.